Writing & History. History is impossible without the written word as one would lack context in which to interpret physical evidence from the ancient past. Writing records the lives of a people and so is the first necessary step in the written history of a culture or civilization.
Lesson Summary. In review, chemical energy is energy stored in chemicals'. Energy is 'the ability to do work. Chemical energy is a type of potential energy that is energy due to the position of an object or objects.
Activation energy may also be defined  as the minimum energy required to start a chemical reaction.   It is the amount of energy required for a chemical reaction to take  place. This is why some chemical reactions require heat (eg.  burning) while others can take place at room temperature (eg.